It is known to produce three-dimensional objects starting from a CAD model of the object layer by layer. In the known process of stereolithography, monomers are polymerised in the presence of photoinitiators by laser radiation. However, only a limited number of monomer types are suitable as materials. In 3D printing technology, ink-jet technology is used in order to bind powder particles in the particular layer at the points corresponding to the cross-section of the object using adhesives. However, this technology, like stereolithography as well, require after-treatment of the blanks produced.
In addition, supporting constructions are required for forming three-dimensional objects having projections, protuberances and lower cavities, in order to prevent distortion or breaking of the three-dimensional object
A different technique for generating three-dimensional models is selective laser sintering. A pulverulent material is thus applied in layers and the particular uppermost powder layer is illuminated using a laser beam at points corresponding to the cross-section of the model. The powder melts or sinters there due to the energy input of the laser. However, the thermal stress of the material is high, so that sensitive polymers are destroyed. Incorporation of biological components, such as for example cells or proteins, is not possible. The generation of hydrogels is also not possible.
A process for forming three-dimensional models is known from French 2 583 334. Therein, a photoinitiator is added to a monomer liquid and the monomer is cured by irradiation. Alternatively, a monomer reacting with a thermal initiator is added to a neutral liquid. However, the accuracy of the formation of the three-dimensional object and the number of useable materials is limited.
Thermoplastic polymers are melted in the technology of Fused Deposition Modelling (FDM). The liquid melt leaves the nozzles as a strand and constructs three-dimensional objects by cooling in air. This process is limited to thermoplastic polymers having a high melt viscosity. The range of the materials used successfully here hitherto is limited to acrylonitrile-butadiene-styrene copolymers and polycaprolactone. The processing temperature thus exceeds 100° C.; this prevents the incorporation of thermally sensitive additives into the 3D object produced.
The object of the invention is the provision of an improved device or an improved process for producing three-dimensional objects.